Due to the trend of making large refrigerators, side-by-side type refrigerators are commercialized. A side-by-side type refrigerator includes a freezing chamber and a refrigerating chamber arranged side by side, a refrigerator body partitioned by a barrier, and a freezing chamber door and a refrigerating chamber door rotatably connected on the front of the refrigerator body to open/close the freezing chamber and the refrigerating chamber.
Specifically, the freezing chamber and the refrigerating chamber include a plurality of shelves on which foods are placed. A plurality of casings are installed inside the freezing chamber and the refrigerating chamber to define a receiving space where foods are preserved. The casing is generally designed to be withdrawn in a drawer type, such that foods are put in or taken out through the opening upper portion of the casing.
According to a related art refrigerator, the internal temperature of the casings provided in the freezing chamber and the refrigerating chamber are maintained at a level substantially equal to the temperature of the space where the casing is installed. For example, the internal temperature of the casing installed inside the freezing chamber is maintained at a level substantially equal to the internal temperature of the freezing chamber.
Therefore, the related art refrigerator has a problem in that the internal temperature of the casing cannot be maintained to be lower than the temperature of the refrigerator.
However, the internal temperature of the casing needs to be maintained at the ultra-low-temperature state, which is lower than the internal temperature of the refrigerator by tens degree Celsius, according to kinds of foods or other reasons.
A separate freezing cycle may be provided in order to differently maintain the internal temperature of the refrigerator and the internal temperature of the casing installed in the refrigerator. However, this method increases a manufacturing cost. In addition, a manufacturing process is complicated and a weight of a product is increased.